import java.io.*; import java.util.*; public class Main { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); int q = sc.nextInt(); int[] values = new int[n + 1]; long[] sums = new long[n + 1]; long[] totals = new long[n + 1]; for (int i = 1; i <= n; i++) { values[i] = sc.nextInt(); sums[i] = sums[i - 1] + values[i]; totals[i] = totals[i - 1] + sums[i]; } StringBuilder sb = new StringBuilder(); while (q-- > 0) { int x = sc.nextInt(); if (totals[n] < x) { sb.append(-1).append("\n"); continue; } int left = 0; int right = n; while (right - left > 1) { int m = (left + right) / 2; if (totals[m] >= x) { right = m; } else { left = m; } } x -= totals[left]; long ans = (left + 1L) * left / 2; left = 0; right = n; while (right - left > 1) { int m = (left + right) / 2; if (sums[m] >= x) { right = m; } else { left = m; } } sb.append(ans + right).append("\n"); } System.out.print(sb); } static class Path implements Comparable { int idx; int value; public Path(int idx, int value) { this.idx = idx; this.value = value; } public int compareTo(Path another) { return value - another.value; } } } class Scanner { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); StringTokenizer st = new StringTokenizer(""); public Scanner() throws Exception { } public int nextInt() throws Exception { return Integer.parseInt(next()); } public long nextLong() throws Exception { return Long.parseLong(next()); } public double nextDouble() throws Exception { return Double.parseDouble(next()); } public String next() throws Exception { while (!st.hasMoreTokens()) { st = new StringTokenizer(br.readLine()); } return st.nextToken(); } }